Lamp with automatic filament shifting means



V. CONT] Nov. 25, 1958 LAMP WITH AUTOMATIC FILAMENT SHIFTING MEANS FiledOct. 18, 1955 3 Sheets-Sheet 1 NOV. 25, 1958 v, co 2,862,147

LAMP WITH AUTOMATIC FILAMENT SHIFTING MEANS Filed Oct. 18, 1955 5Sheets-Sheet 2 /7 TTOP/VE'Y)? LAMP WITH AUTOMATIC FILAMENT SHIFTINGMEANS Filed Oct. 18, 1955 V. CONT] I Nov. 25, 1958 3 Sheets-Sheet 3 a wW v Z 3 Z 4 I 0 m w M 8 2 M 2 w nm n uw a 0 wan" m M, 5 N f 6 I E j w 0j J 2 m x 4 2 a z w w mw m a 0 .2 a 8 0 w 6 2 I a HHW #w W HHHHI. m 0.4/0 6 0 m fl H/ a 2 4 9 40 w j 2 f/// M 2 United States Patent "ice 1LAMP WITH AUTOMATIC FILAMENT SHIFTING MEANS Vincent Conti, New York, N.Y.

Application October 18, 1955, Serial No. 541,148

18 Claims. (Cl. 315-65) The present invention relates to means, in alamp having a plurality of filaments, for causing only one filament at atime to be energized and for automatically shifting electricalconnection to a second filament in case the first filament should break.

The invention is here disclosed embodied in an incandescent bulb useablefor illumination purposes, but it is applicable for use in other typesof bulbs as well.

It is often desired that the failure of a filament should not result incomplete failure of the bulb. Accordingly, a plurality of filaments maybe incorporated into the bulb, only one of those filaments normallybeing energized, and means may be provided which, upon failure of thenormally energized or primary filament, will automatically shiftelectrical connection to the normally unenergized or secondaryfilaments. Various arrangements have been proposed in the past toaccomplish this end, but they are all fairly expensive and complicated,or else are not sulficiently reliable in operation.

In accordance with the present invention, an arrangement has beendevised which is easily assembled, does not add appreciably to the costof the bulb, and will perform the desired functions in a reliable andwell nigh foolproof manner. The arrangements of the present inventionare particularly well adapted for incorporation into bulbs which may bemounted either base-up or base-down, and will in most instances functioneffectively no'matter in which of these ways the bulbs are mounted.

Broadly described, the invention utilizes means for completingelectrical connection to the secondary filament or filaments, whichmeans is operatively associated with the primary filament and sensitiveto the position thereof. If the primary filament should break for anyreason the separated segments of that filament will fall, and theoperative association between the means and the primary filament is suchthat when the latter falls the means will be modified to produce thedesired result. In one form the means is mounted on and slidable along alead connected to one terminal of the lamp and is supported by theprimary filament. When the primary filament breaks the support will bedestroyed, the means will move downwardly, and that downward movementwill elfectuate the desired electrical connection to the secondaryfilament. This can be done either by having the means directly connectedto and supporting one end of the secondary filament, so that when themeans falls that filament end will move into electrical connection withthe lead, or that filament end can be physically mounted on butinsulated from the lead, the means itself being electrically connectedto the lead and, when it falls, engaging and making electricalconnection with the appropriate end of the secondary filament. Accordingto another form an end of the primary filament is electrically connectedto the lead and the means is electrically connected to the correspondingend of the secondary filament, the means normally being insulated fromthe lead but the movement of the primary filament attendant upon a breaktherein causing the primary filament to 2,862,147 Patented Nov. 25, 1958engage the means and thus complete electrical connec-.

tion to the secondary filament.

While the present invention is here specifically disclosed as relyingexclusively on the force of gravity for eflfecting the desired results,it will be appreciated that the use of auxiliary means such as springsto make the switching action even more positive is not necessarilyprecluded. However, the use of springs or other devices is not at allessential to the operation of the instant devices. l e f To theaccomplishment of the above, and to such othe objects as may hereinafterappear, the present invention relates to lamp structure for effectingautomatic switch-, ing from a primary to a secondary filament, asdefined in the appended claims and as described in this specification,taken together with the accompanying drawings, in which:

Fig. l is a perspective view of a lamp having two filaments, one abovethe other, constructed according to the present invention, the lampbeing shown with the primary filament active;

Fig. 2 is a fragmentary view similar to Fig. 1 but showing the positionwhich the parts assume when the primary filament breaks;

Fig. 3 is a view similar to Fig. 1 but illustrating one manner in whichthe invention may be applied to a bulb having primary, secondary andtertiary filaments adapted to be sequentially energized, the primaryfilament being shown energized;

Fig. 4 is a fragmentary view similar to Fig. 3 but showing the positionswhich the parts assume when the primary filament breaks;

Fig. 5 discloses the invention embodied in a two-filament bulb ofspecifically different construction from that shown in Fig. 1;

Fig. 6 discloses a structure comparable to that of Fig. l but with aspecifically difierent arrangement of parts;

Fig. 7 is similar to Fig. 6 but showing the position which the partsassume when the primary filament breaks;

Fig. 8 is a perspective view of a bulb constructed according to thepresent invention in which three filaments all positioned at the samelevel are embodied, the primary filament being shown energized;

Fig. 9 is a view similar to Fig. 8 but showing the position which theparts assume when the primary filament breaks; a

Fig. 10 is a perspective viewof .yet another two-filament bulb in whichyet another embodiment of the present invention is disclosed, theprimary filament being shown energized;

Fig. 11 is a view similar to Fig. 10 but showing the position which theparts assume when the primary filament breaks;

Fig. 12 is a side elevational view of yet another em bodiment of thepresent invention, the bulb being shown in a base-up position;

Fig. 13 is a cross sectional view on an enlarged scale of theoperativeparts of the bulb of Fig. 12, the primary filament being shown broken;and v Fig. 14 illustrates the bulb of Fig. 12 in a base-down position. 7

In the embodiment of Figs. 1 and 2 the lamp comprises a base generallydesignated 2 and an evacuated bulb generally designated 4. The base 2 isprovided, as is.

v are respectively electrically connected to the terminals 6 and 8. Theends 20:: and 22a of the filaments 20 and 22 3 respectively arephysically and electrically connected to appropriate points on the lead26. The ends b and 22b of the filaments 20 and 22 respectively arephysically connected to insulators 28 and on the lead 24.

The means for completing anelectrical circuit through one or the otherfilaments 20 or 22 is generally designated 32. It comprises a conductivewire coiled about the vertical portion 24a of the lead 24 at 34 so as tomake electrical connection therewith and be slidable therealong. Arms 36and 38 extend from the coiled portion 34 toward the filaments 20 and 22respectively, those arms terminating in loops and 42 respectively whichsurround the filaments 20 and 22 respectively adjacent their ends 20band 22b respectively. 7

When the lamp of Figs. 1 and 2 is in its base-up position there shown,the filament 22 constitutes the primary filament and the filament 26 isthe secondary filament. The loop 42 rests upon and is supported by thefilament end- 225 and makes electrical connection therewith via thelooped portion 34 and the arm 38. Thus the filament 22 is energized. Theloop 40 is supported by the arm 36 out of engagement with the filamentend 20b, and consequently the filament 20 is not energized. In order toprevent vibration from causing the loop 40 to intermittently engage thefilament 20 and energize it, the sides of the loop 40 may be coveredwith insulating material 44, and insulating material 46 maycorrespondingly cover the sides of the loop 42.

'As shown in Fig. 2, if the filament 22 should break it would fall andconsequently. would no longer support the loop 42 and the remainder ofthe means 32. Hence the coiled portion 34 will slide downwardly alongthe lead 24a until the loop 40 rests on the filament 20, at which timeelectrical connection will be made to the filament 20 and that filamentwill beenergized.

If the bulb of Figs. 1 and 2 should be inverted to a base-down position,the structure will operate in the same way, except that the filament 20would become the primary filament and the filament 22 would become thesecondary filament;

Figs. 3 and 4 disclose a structure essentially similar to that shown inFigs. 1 and 2, and similar reference numerals are applied to similarparts. However, the embodiment of Figs. 3 and 4 difiers from'that ofFigs. 1 and 2 primarily in the following respects: In addition to thefilaments 20 and 22, a third filament 20 is employed.

The end 22b of the primary filament 22 is constituted by a short lengthof structurally strong material pivotally connected to the end of thelead portion 24a at 48, and the end 20b of the intermediate filament -20is similarly constructed and pivotally connected at to the insulator 28.The switching means 32 comprises two coiled portions 34 and 34', theloop 42' at the end of the arm 38 depending from the coiled portion 34being received around the part 22b. The loop 40 is not only connected tothe coiled portion 34 by the arm 36, as before, but is also connected tothe coiled portion 34 by the arm '38. A loop 40, which surrounds thethird filament 20', is supported by arm 36 connected to coiled portion34'. The loops 42', 40 and 40' are of gradually increasing size. The'loop 40' is provided at its top and bottom with curved shields 49aligned with the filament end 20b.

Inthis embodiment, the filament 22 constitutes the primary filament, thefilament 20 constitutes the secondary filament, and the filament 20'constitutes the tertiary filament. When the filament 22 is intact themeans 32 will be supported by the loop 42' so thatthe loop 40 is spacedfrom the filament 20 and the loop 40' is spaced from the'filament 20. V

-It will be noted that'electrical connection to the end 22b' of thefilament 22 is eifectuated independently of the means 32, and hence itis not essential that the loop 42' make electrical connection with thefilament end 22b. Since the filament ends 20b and 22b are formed ofsubstantially rigid material, much stronger than the actuallyincandescent portion of the filament proper, the reliability of supportof the means 32 is greatly enhanced. These modifications could, ofcourse, be incorporated even into those embodiments where they are notspecifically illustrated.

If the primary filament 22 should break the support which it affordedthe means 32 will be destroyed and consequently the coiled portions 34and 34 will slide downwardly along the lead 24a until the loop 40engages the filament end 26b. The means 32 will then be supported by thefilament 20 and that filament will be energized. Since the loop 40' islarger than the loop 40, no energization of the tertiary filament 20'will take place. This position of the parts is illustrated in Fig. 4. Itmay be noted that an adidtional advantage of the use of the pivotallymounted substantially rigid portion 22b (or 20b) is that said portion,when it pivots downwardly, will because of its own weight and rigiditytend to pull the means 32 downwardly, and thus will more readily ensurethat proper electrical connection with the next succeeding filament isefiectuated.

If the filament 20 of Fig. 4 should break the means 32 will then slidedownwardly along the lead 24a an additional distance, until the loop 40rests upon and makes electrical connection with the tertiary filament20. It may be noted that when the loop 40' rests upon the filament 20'it will be supported by one of the shields 49 which extend along asubstantial portion of the length of the filament 20' and consequentlydistribute the weight of the means 32, thus rendering it most unlikelythat the weight of the means 32 will have any appreciable effect on thelongevity of the filament 20'. It will be appreciated that the shields49 could be employed in other embodiments of my invention for thispurpose, even when they are not there specifically disclosed.

If the bulb of Figs. 3 and 4 should be inverted, it would function insubstantially the same manner as just described, the filament 22remaining the primary filament and the filaments 20 and 20 remaining thesecondary and tertiary filaments respectively.

It will be understood that while the embodiments of Figs. 3 and 4 showsthree filaments, any number of filaments could be employed using-theprinciples there disclosed. 9

Fig. 5 illustrates my invention embodied in a lamp of specificallydilferent design. There the ends 20a and 22a of the filaments 20 and 22respectively are physically and electrically connected to lead 26, asbefore. The filament ends 20b and 22b are physically connected to andsupported by blind lead 52 by means of insulators 28 and 30respectively. The lead 24 which is electrically connected to the tipterminal 6 extends centrally of the bulb 4. The portion 34 ofthe means32 iscoiled about and slidable along the live lead 24' and its arms 36and 38 carry at their ends loops 40a and 42. The loop 42 may be in allrespects similar to the loop 42 of Fig. l, but the loop 40:: asspecifically disclosed in Fig. 5 is quite small and closely engages thefilament end 20b, thus being similar to the loop 42' of Fig. 3. Becauseof the use of a small loop 49a, the filament 20 in the embodiment ofFig. 5 will be the primary filament whether the lamp is in the positionshown or inverted.

If, in the embodiment of Fig. 5, the insulating material 44 is wholly orpartially eliminated from the loop 42, the means 32 would function toachieve the desired results even if the bulb were mounted at ahorizontal position. The primary filament 20 would support the means 32against rotative sliding around the lead 24' with the sides of the loop42 spaced from the end 22b of the filament 22. When the primary filament20 breaks that support will be lost, the coiled portion 34 of the means32 will rotatively slide over the lead 24, and consequently the hatedside-of the loop 42 will engage the end 22b of the secondary filament22, thus energizing the latter.

This same principle could, also, be employed in connection with otherembodiments, such as the embodiments of Figs. 3-4, 6-7 and 8-9.

The embodiment of Figs. 6 and 7 is essentially similar to that of Figs.1 and 2. However, the ends 20b and 22b of the filaments 20 and 22 areshown as formed of strong rigid elements similar to the similarlynumbered parts in Fig. 3. In addition, the arm 38 of the means 32 doesnot carry a loop 42 but is instead directly physically secured to thefilament end 22, as by's'older 54. Hence the operation of the embodimentof Figs. 6 and 7 will be essentially similar to that of Figs. 1 and 2except that the filament 22 will remain the primary filament no matterin What position the lamp may be mounted. Moreover, in the embodiment ofFigs. -6 and 7 the element 30' to which the filament end 22b ispivotally connected at 48 is shown as conductive, thus effectuatingelectrical connection to the filament 22 independently of the means 32.Hence it is immaterial whether the arm 38 be electrically connected tothe lead 24a or to the filament end 22b. Alternatively, if electricalconnection is ettectuated between the arm 38 and the filament end 22band with the use of an element 30' which is conductive as shown,reliance need not be placed upon electrical connection between thecoiled portion 34 and the lead 24, and hence the coiled portion 34 maybe more loosely wound around the lead 24a than would otherwise be thecase. It will be understood that these modifications could be carriedover into the other embodiments even where not specifically illustrated.

The loop 40 of Figs. 6 and 7 may be provided at its top and bottom, asillustrated, with small permanent -magnets 56. When the primary filament22 breaks, as

illustrated in Fig. 7, one or the other of these magnets 56, dependingupon the position of the lamp, will engage with the filament 20 and willserve twofunctions. They distribute the weight of the means 32 along asubstantial portion of the length of the filament 28, in this wayparalleling the effects of the shields 49 on the loop 40 of Fig. 3, andin addition they serve to ensure adequate physical and electricalcontact between the loop 48 and the filament 28 even when the lamp issubjected to vibration. Alternatively, the end 28b of the filament 20could be permanently magnetized in place of or in addition to the use ofthe magnets 56 carried by the loop 40.

Figs. 8 and 9 disclose the invention as embodied in a lamp having aplurality of filaments disposed at the same level. In Figs. 8 and 9 thelead 24 is connected to the side terminal 8, while a plurality of leads5%, 60 and 62 are all connected to the tip terminal 6. The filaments 64,66 and 68 are respectively the primary, secondary and tertiaryfilaments. Their ends 64a, 66a and 68a are connected electrically andphysically to the leads 58, '60 and 62 respectively. Their other ends64b, 66band 681) are physically connected to insulator 70 at the tip ofthe lead 24. The coiled portion 34 of the means 82 has three arms 72, 74and 76 which carry loops 78, 80 and 82 respectively, each ofincreasingly greater size, which surround the filament ends 64b, 66b and68b re spectively. The size of the loop 78 is such that when the primaryfilament 64 is intact the loops 80 and 82 will be held out of engagementwith their respective filament ends 661) and 68b. .Thus only the primaryfilament 64 will be energized. When, as illustrated in Fig. 9, theprimary filament 64, will slide downwardly along the lead 24 until it issupported by engagement between the loop 80 and the secondary filament66, thus energizing that filament. The size of the loop 82 will ensure,however, that the tertiary filament will not be energized. If thesecondary filament 66 should break then the means 32 will slidedownwardly until the loop 76 rests on and energizes the tertiaryfilament 68. Although this particular construction is disclosed in alamp having three filaments, it will be apparent that a similarconstruction could be employed in lamps having two filaments or morethan three filaments.

In the embodiment of Figs. 10 and 11 the upper end of the lead 24a isprovided with an insulating coating 84 above and below which widerconductive elements 86 and 88 are positioned, those elements beingelectrically connected to the lead 24a. The end 22b of the filament 22is provided with a loop 90 adapted to slide along the insulated portion84 and to engage and make electrical connection with one or the other ofthe conductive elements 86 or 88. The arm 36 of the means 32 is directlyelectrically and physically attached to the end 20b of the filament 20,and the arm 38 is directly physically secured to the end 22b of thefilament 22 but is electrically insulated therefrom, as by theconnecting means 92. In this embodiment, when the filament 22 is intact,the means 32 will maintain the filament end 22b in a positionintermediate between the conductive elements 86 and 88, thus preventingenergization of the secondary filament 22. The primary filament 20 willbe energized via the coiled portion 34 and the arm 36 of the means 32.(Alternatively, as in Fig. 6, the element 30 to which the filament end20b is pivotally connected at 50 may be conductive, in which case thereis no necessity for the means 32 to be electrically connected to thelead 24a, as will become apparent.) When the filament 20 breaks themeans 32 is no longer supported thereby, and consequently the filamentend 22b will be permitted tofall into engagement with the lowermost ofthe conductive el6- ments 86 or 88 depending upon the position of thelamp, and the secondary filament 22 will then be energized.

In the embodiment of Figs. 12-14 the lead 24a is provided with enlargedportions 94 and 96 conductively connected thereto. Two compositeelements 98 and 100 are slidably mounted on the lead 2401 between theportions 94 and 96. The element 98 comprises conductive parts 102 and104 separated by insulation 106, the conductive parts 102 and 104 beingheld out of conductive engagement with the lead 24a proper but the part102 being engageable with the conductive portion 94 when the bulb is inthe position shown in Figs. 12 and 13. The element 100 comprisesconductive parts 108 and 110 separated by insulation 112, the parts 108and 110 being held out of conductive engagement with the lead 24a properbut the part 108 being engageable with the conductive portion 96 whenthe bulb is positioned in base-down position as shown in Fig. 14. Thefilament end 2211' is physically and electrically connected to the part102 and the filament end 20b is physically and electrically connected tothe part 108. .The part 104 carries, by means of wire 114, a loop 116which surrounds but is normally out of engagement with the filament end22b. The part 110 carries, by means of wire 118, a loop 120 whichsurrounds but is normally out of engagement with the filament end 2%. Asubstantially rigid wire 122 connects part 102 with part 110, and asubstantially rigid wire 124 connects part 104 with part 108, the wires122 and 124 maintaining the spacing between the elements 98 and 100,that spacing, as shown, being somewhat less than the spacing between theparts 94, 96.

When. the bulb is in base-up position, and when the filament 22 isintact, as shown in Fig. 12, the filament 22 will be energized by acircuit which may be traced through the lead 24a, portion 94, part 102,filament 22 and lead 26. The filament end 2% will not be electricallyconnected to lead 24a because the part 108 is separated from the portion96 and because the loop 120 which is electrically connected to the part102 is out of engagement with the filament end 20b. If now, as shown inFig. 13, filament 22 should break, its end 22b would engage with loop116, and consequently the end 20b of the filament 20 would be connectedwith lead 24a via part 108, wire 124, part 104, wire 114, loop 116,filament end 22!), part 102 and portion 94.

If the bulb should be in base-down position, as shown in Fig. 14, thesame results will obtain, except that now part 108 will be in engagementwith the portion 96, and the filament 20 will become the primaryfilament and the filament 22 will become the secondary filament.

It will be appreciated from the above discussion that in each caserelative movement between the primary filament and the lead attendantupon the breaking of the primary filament will cause connection to bemade to the secondary filament to energize the latter, and this by meansof simple structure which may rely exclusively upon the force of gravityto accomplish the desired results. A number of embodiments of theinvention have been here disclosed which illustrate but some of the waysin which the principle of my invention can be embodied. Of course, thereare many types of lamp and bulb constructions, and I have illustrated myinvention only in connection with a limited number of them, but theinvention is clearly applicable to bulb constructions other than thosehere specifically disclosed and many variations may be made in thespecific details of the structure, all within the spirit of theinvention as defined in the following claims.

I claim:

1. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when said primaryfilament breaks, said means being mounted on said lead, slidabletherealong, and comprising a conductive structure physically connectedto said primary filament and normally spaced at a given point from oneof said lead and said secondary filament, said space defining an opencircuit between said secondary filament and said lead, whereby relativemovement between said primary filament and said lead attendant upon thebreaking of said primary filament causes said means to slide along saidlead'until said space disappears, thereby electrically connecting saidother end of said secondary filament to said lead.

2. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals,'an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when saidprimaryfilament breaks, said means being mounted on said lead to beslidable therealong and having a first portion normally engageable withand supported by said primary filament, and a second portion operativelyengageable with said secondary filament and effective to cause relativemotion between said lead and either one of said secondary filament andsaid second portion, thereby to complete electrical connection betweensaid lead and said other end of said secondary filament, whenever saidprimary filament breaks and said means moves relative to said lead.

3. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between theother end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connectingthe otherendof said secondary filament to said other terminal when said primaryfilament breaks, said means being mounted on said lead, slidabletherealong and electrically connected thereto, said means comprising afirst portion normally engageable with and supported by said primaryfilament and a second portion normally spaced from said secondaryfilament but movable into engagement therewith to complete theelectrical circuit thereto whenever said primary filament breaks andthus destroys the support for said means.

4. The lamp of claim 3, in which said second portion of said meanscomprises a member normally positioned above said secondary filament andmovable downwardly to rest upon said secondary filament when saidprimary filament breaks.

5. The lamp of claim 3, in which one of said portions comprises a loopnormally extending at least partially around the corresponding filamentand movable downwardly to rest upon said filament.

6. The lamp of claim 3, in which the sides of said loop are covered withinsulation but the upper and lower portions of said loop are exposed.

7. The lamp of claim 3, in which one of said portions comprises a memberextending over and along the length of the corresponding filament for anappreciable distance, whereby the weight of said means is distributedover a substantial portion of the length of said filament when saidmeans is supported thereby.

8. The lamp of claim 3, in which one of said portions comprises apermanent magnet engageable with the corresponding filament when saidmeans is supported thereby,

thus ensuring engagement between said portion and said filament.

9. The lamp of claim 3, in which one of said filaments comprises aconductive portion of appreciable strength adjacent said lead, thecorresponding portion of said means being engageable therewith when saidmeans is supported thereby.

10. An electric lamp comprising a bulb having terminals, primary,secondary and tertiary filaments in said bulb, said secondary filamentbeing adapted to light when said primary filament breaks and saidtertiary filament being adapted to light when both said primary andsecondary filaments break, electrical connections between one end ofeach of said filaments and one of said terminals, an electricalconnection between the other end of said primary filament and the otherof said terminals, an elongated vertical lead electrically connected tosaid other terminal, and means for sequentially connecting the otherends of said secondary and tertiary filaments respectively to said otherterminal when said primary and secondary filaments respectively break,said means being conductive,

mounted on said lead so as to be slidable thereover, and having first,second and third portions, said first portion normally being engageablewith and supported by said primary filament, said second and thirdportions being spaced from said secondary and tertiary filamentsrespectively by progressively increasing distances, breakage of saidprimary filament causing said means to slide over said lead until saidsecond portion engages with and is supported by said secondary filament,thereby electrically connecting said other end ofsaid secondary filamentto said lead, breaking of said secondary filament causing said means toslide over said lead until said third portion engages with and issupported by said tertiary filament, thereby electrically connectingsaid other end of said tertiary filament to said lead.

11. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, a lead electrically connected to said otherterminal and having a substantially vertical portion comprising aninsulated part above a conductive part, and means for connecting theother end of said secondary filament to said other terminal when saidprimary filament breaks, said means comprising a structure operativelyconnected between said primary and secondary filaments, supported bysaid primary filament and in turn supporting said other end of saidsecondary filament adjacent the insulated part of said lead, breaking ofsaid primary filament removing the support for said means and causingsaid other end of said secondary filament to fall to and engage theconductive part of said lead, thereby causing said secondary filamenttolight.

12. The lamp of claim 11, in which said other end of said secondaryfilament is looped around the insulated part of said lead, theconductive part of said lead comprising a portion of increased diameterpositioned below said other end of said secondary filament, said otherend of said secondary filament falling to rest on said conductiveportion of increased diameter when said primary filament breaks.

13. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when said primaryfilament breaks, said means comprising a first portion mounted on saidvertical lead so as to be slidable therealong, a second portionextending from said first portion and resting on said primary filament,and a third portion extending from said first portion and normallyspaced from one of said lead and said secondary filament, said spacedefining an open circuit between said secondary filament and said lead,whereby relative movement between said primary filament and said leadattendant upon the breaking of said primary filament causes said meansto slide along said lead until said space disappears, therebyelectrically connecting said other end of said secondary filament tosaid lead.

14. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said hub, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when said primaryfilament breaks, said means comprising a first portion mounted on saidvertical lead so as to be slidable therealong, a second portionextending from said first portion and resting on said primary filament,and a third portion extending from said first portion and normallyspaced from said secondary filament, said space defining an open circuitbetween said secondary filament and said lead, whereby relative movementbetween said primary filament and said lead attendant upon the breakingof said primary filament causes said means to slide along said leaduntil said space disappears, thereby electrically connecting said otherend of said secondary filament to said lead.

15. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said 10 secondary filament to said other terminal when said primaryfilament breaks, said means comprising a first portion mounted on saidvertical lead so as to be slidable therealong, a second portionextending from said first portion and resting on said primary filament,and a third portion extending from said first portion and connected tosaid other end of said secondary filament, said other end of saidsecondary filament normally being spaced from said lead and movablerelative thereto along with said third portion of said means, said spacedefining an open circuit between said secondary filament and said lead,whereby relative movement between said primary filament and said leadattendant upon the breaking of said primary filament causes said meansto slide along said lead until said space disappears, therebyelectrically connecting said other end of said secondary filament tosaid lead.

16. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when said primaryfilament breaks, said means being conductive and comprising a firstportion mounted on said vertical lead so as to engage and beingelectrically connected to the latter and so as to be slidabletherealong, a second portion extending from said first portion andresting on said primary filament, and a third portion extending fromsaid first portion and normally spaced from one of said lead and saidsecondary filament, said space defining an open circuit between saidsecondary filament and said lead, whereby relative movement between saidprimary filament and said lead attendant upon the breaking of saidprimary filament causes said means to slide along said lead until saidspace disappears, thereby electrically connecting said other end of saidsecondary filament to said lead.

17. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals, anelectrical connection between the other end of said primary filament andthe other of said terminals, an elongated vertical lead electricallyconnected to said other terminal, and means for connecting the other endof said secondary filament to said other terminal when said primaryfilament breaks, said means being conductive and comprising a firstportion mounted on said vertical lead so as to engage and beingelectrically connected to the latter and so as to be slidabletherealong, a second portion extending from said first portion andresting on said primary filament, and a third portion extending fromsaid first portion and normally spaced from said secondary filament,said space defining an open circuit between said secondary filament andsaid lead, whereby relative movement between said primary filament andsaid lead attendant upon the breaking of said primary filament causessaid means to slide along said lead until said space disappears, therebyelectrically connecting said other end of said secondary filament tosaid lead.

18. An electric lamp comprising a bulb having terminals, primary andsecondary filaments in said bulb, said secondary filament being adaptedto light when said primary filament breaks, electrical connectionsbetween one end of each of said filaments and one of said terminals,

11 terminal, and means for connecting the other end of said secondaryfilament to said other terminal when said primary filament breaks, saidmeans being conductive and comprising a first portion mounted on saidvertical lead so as to engage and being electrically connected to thelatter and so as to be slidable therealong, a second portion extendingfrom said first portion and resting on said primary filament, and athird portion extending from said first portion and connected to saidother end of said secondary filament, said other end of said-secondaryfilament normally being spaced from said lead and movable relativethereto along with said third portion of said means, said space definingan open circuit between said secondary filament and said lead, wherebyrelative movement between said primary filament and said lead attendantupon the breaking of said primary filament causes said means to slidealong said lead until said space disappears, thereby electricallyconnecting said other end of said secondary filament to said lead.

References Cited in the file of this patent UNITED STATES PATENTS vJameson June 20, 1882

